Scale and/or corrosion inhibiting composition
AssigneeAshland Inc.
InventorsPavol Kmec, Dwight E. Emerich
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Abstract
This invention relates to a scale inhibiting composition for aqueous systems comprising (a) polyaspartic acid, and (b) a water soluble phosphonated oligomer. The compositions are effective scale and/or corrosion inhibitors, but are also advantageous from an environmental standpoint because they are non-toxic, contain no heavy metals, and have little or no phosphorus. They also have sufficient calcium/hardness tolerance, are chlorine/bromine stable, and are effective corrosion inhibitors.
Claims10
A scale and/or corrosion inhibiting composition comprising:
- (a) polyaspartic acid;
- and
- (b) a water soluble phosphonate oligomer salt having the general formula:
- H[CHRCHR]n—PO3M2
- wherein
- (1) at least one R group in each unit is selected from the group consisting of a COOM, CH2OH, sulphono, and a phosphono group;
- (2) the other R group which may be the same as, or different from, the first R group, is selected from the group consisting of hydrogen, COOM;
- hydroxyl;
- phosphono;
- sulphono;
- sulphato;
- C1-7 alkyl;
- C1-7 alkenyl;
- a carboxylate, phosphono, sulphono, sulphato, and/or hydroxyl substituted C1-7 alkyl group;
- and a carboxylate, phosphono, sulphono, sulphato, and/or hydroxyl substituted C1-7 alkenyl group;
- (3) each M is a cation such that the phosphonated oligomer is water soluble;
- (4) n is a number from 1 to 6;
- and
- (5) and the weight ratio of phosphonated oligomer to polyaspartic acid to is from 1:4 to 1:9.
A method for inhibiting the formation of scale in an aqueous system comprising:
- introducing the composition of claims 1, 2, 3, 4, 7, 8, or 9 into said aqueous system in an amount effective to inhibit the formation of scale wherein said composition is used in concentration from 10 ppm to 200 ppm based on the total of components (a) and (b).
Dependencies are inferred from the claim text.